In printing performed by a printer, dots of coloring material such as ink and toner are formed. For printers of this type, technologies have been proposed to control driving signals for forming individual dots based on dot formation conditions of neighboring dots. For example, technology is disclosed in which different driving signals are utilized depending on whether a dot to be formed is an isolated dot or a consecutive dot (see Japanese Patent Application No. H09-277604, Japanese Patent Application No. 2002-292929, Japanese Patent Application No. 2008-49694, and Japanese Patent Application No. H10-157205, for example). Specifically, by performing control such that a pulse width of a driving signal when forming isolated dots is made wider than the pulse width of the driving signal when forming consecutive dots, isolated dots is made wider than the pulse width of the driving signal when forming consecutive dots, isolated dots can be reliably formed on a recording sheet.